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Abekas A60 Digital Disk Recorder Ethernet Manual Aug88

1. ET En lt lt gt a lt lt lt 0 frame 0 frame 1 lf rendered frames are being transferred to an A60 that will be used later in an editing environment that uses field two dominance eg edits are made between field one and field two rather than on frame boundaries It may be more appropriate to transfer the frames starting with the second field rcp myframe 60 20 places the frame at fields 00 20 and 00 21 rather than 00 20 and 00 20 Write Protection The A60 has the ability to Write Protect or Record Lockout segments of the Disk An attempt to transfer to a Record Locked out section will result in an appropriate Write Protected error message Note that Record Lockout can be changed using the protect and unprotect commands from the Ethernet remote software Abekas FTP The following is the example of an FTP transfer files to and from the A60 Beidface type indicates what is entered by the user host ftp a60 Connected to a60 220 Abekas A60 FTP a60 250 User OK ftp gt type image 200 TYPE OK ftp gt send piccy 25 200 PORT spec accepted host 192 9 200 6 port 1061 150 OK here goes 226 File Transfer OK 699840 bytes sent in 4 92 seconds 1 4e 02 Kbytes s ftp gt send sym symb576 rgb 25 rgb 200 PORT spec accepted host 192 9 200 6 port 1062 150 OK here
2. m 33 m 33 TERRENI 34 General ern d desse EEA EEEE 34 COPYLigRt Notice Tm 35 Release NOLO MORIR NND RE 36 TroublIeshoot IDE 0 cioe ero Poor are A 38 38 Ethernet TT 38 Ethernet Address oco ite teens rhesei vos ereesbesedevesoxu etu ctn 38 Internet Address oov a dn 39 650005 5 Y 39 giri c 39 LOO Biradera a e M 39 Ner e rence auina i 40 E ELM 40 Colorized V 1060 soe cde END oN eia 40 Field Service oie cvi Cn XE CU MER LEER A VERG 40 Doing your own Debugging ccccccccssssersescscssssessconsssccsseccesescossserocssancesseetecscesesseccereesecs 41 Debug Poft A 41 Debug a 41 High Level Debut 42 TOP DGG 22252258 PN 43 IP 43 Ethernet Debug iin 43 E AE AE AOE E EN AE AE AE 45 ExXampIe Programs na E A 49 06001 E E M 50
3. int was closed now_closed Notify_value value was_closed int window_get frame FRAME CLOSED value notify_next_event_func frame event arg type now_closed int window_get frame FRAME_CLOSED if was_closed l now closed If now closed close_connection else open_connection return value 60 Ethernet Manual Format 1 Width 64 Height 64 Depth 1 Valid bits 16 0x0000 0x0000 Ox0000 0x0000 0x0000 0x0000 0 0000 0x0000 0 0000 0x0000 0 0000 0x0000 0 0000 0 0000 0 0000 0x0000 0x0000 0 0000 0 0000 0x0000 Ox0000 0 0000 0 0000 0 0000 0x0000 0x0000 0 0000 0 0000 0x0000 0x0000 0x0000 OxQ FF OxFFFF OXFFFF OxFFCO 0x0622 0x2222 0 2222 0x2240 0x0444 0x4444 0x4444 0x4440 OxOSFF OxF911 0x1115 0x3140 OxO4FF OxF S88 0x888A 0xDSCO OxO6FF OxF A22 0x223E 0xB240 0x0444 0x445F OxFFCS 0x7440 0x051 1 0x111F OXFF90 0x 1140 0x0488 0x889F O XFF88 0 88 0 OxOBES3 OxFFR2 0x2240 Ox0O4E7 OxDFSF OxFFC OxE440 OxOSF 3 Ox9F 1F OxFFO 140 OxO4EB OxOF OF OxFFSF OxBF3F OxFFEF 4 4 7 OxDFSF OxXFC40 Ox9F OxFFGF OxXFD40 OxO4EB OxGF9F OxFFOF OxFCCO OxBF3F OxFE40 OxO4FF OxDFSF OxFFCF OxFC40
4. 52 BOD ICO m 55 MYD ERO 56 BODEN IN eink 58 guru cm 58 FTP Implementation u a neh 59 arr gr AM vr A 59 Opening Message ioo md aeri a ea a 59 Commands and RESpPoOnse ccsscscscssscsccssccssccsceceeccsccccssnsssscccssssescscsssssseeeas 59 File MT 62 flog n Implementation ccccccccccccccssccccsssecsssscsscssccssssscccsssscescecesecsccsessccccessssncsscesenscscecs 62 rsh e epis E aa 63 t p Implement erneuern 64 Bibliography aaas a EAEN ee ER EE E 65 Related Documents from AeKas ssssssccsscscssscccescccccsscccessscscsacesccccscsesesssesessescscececs 65 ARPA Publications a a 65 Ethernet spots n EON aaaea aa ae Eua be EUH ERR TNCS 66 Other Background Reading ccccccccccccsscsssscscssssssssccvccccecosescccccsocsacesscacencesecsesccssesssesceees 66 A60 Ethernet Manual h Ethernet Ethernet is a Local Area Network LAN Standard originally developed at Xerox Palo Alto Research Center Ethernet interconnects a group of computers referred to as hosts or nodes with a single 50 Q coaxial cable with terminations at both ends Data is passed serially at 10MHz in the form of packets that is in chunks anywhere from
5. IP is the layer immediately on top of Ethernet that adds Network addressing information to the packet These Internet addresses allow IP packets to be transferred to other networks not just Ethernet It is similar to the way that Containerized freight can be carried equally well by road rail or sea TCP provides an error free bidirectional communications channel above which other utilities such as a remote login or file transfer can be built TCP works by giving each packet a sequence number so that a message or file can be reassembled even if the packets arrive in the wrong order TCP also has an acknowledgement mechanism whereby the receiver replies with the latest complete sequence number it has assembled so that should a packet get lost or delayed in the network the sender will retransmit the missing packet if it hasn t been acknowledged within a reasonable timeout period The third TCP mechanism is the window which limits the amount of unacknowledged data the sender can send out so that it can t get too far ahead if the receiver is missing a packet from earlier in the message For the majority of File transfers or TCP connections there is no data lost All the packets arrive in the correct order The power of the TCP IP protocols lies in the fact that they are not restricted to running on a single local area network The ARPA Internet for example combines over a 100 different networks and includes satellite links to research faciliti
6. OxOSFF Ox9F 7 OxF 140 OxO4FF Ox9F OF OxESCO 0x0622 0x2222 0x2222 0 2240 0x0444 0x4444 0x4444 0x4440 0x0511 0x1111 0x1111 0x1140 OxFFFF OxFFFF OxFFCO 0 0000 0 0000 Ox0000 0 0000 0x0000 0x0000 0x0000 0 0000 0 0000 0 0000 0x0000 0x0000 0 0000 0 0000 0 0000 0 0000 0 0000 0 0000 0 0000 0 0000 0x0000 0 0000 0 0000 0 0000 0x0000 0x0000 0x0000 0x0000 0x0000 0 0000 0 0000 0 0000 0x0000 0x0000 0 0000 0 0000 0 0000 0x0000 0x0000 0x0000 0 0000 0 0000 0 0000 0 0000 0 0000 0 0000 0 0000 0 0000 0 0000 0 0000 0 0000 0 0000 0x0000 0x0083 0 8700 Ox0000 0 0000 0x0084 0x4880 0 0000 0x0000 0x0 144 0x0880 0 0000 0x0000 0x0 144 0x0980 00000 00000 0x0 147 0 8 80 000 0 0000 0x0224 0 4 60 0 0000 0x0000 4 0x4880 0x0000 0x0000 0x0224 0x4880 0x0000 0 0000 0x0223 0x8700 0 0000 0 0000 0x0000 0 0000 0x0000 0x0000 0x0000 0x0000 0x0000 0 0000 0x0000 0 0000 0 0000 0 0000 0x0000 0x0000 0 0000 0 0000 0x0000 000 0 0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 0x0000 55 mycp c 56 mycp c example of a homebrew rcp this version works for rgb and always writes to the same frame 1988 Abekas Vi
7. 46 up to 1500 bytes or characters Each packet carries addressing information to show its source and destination Unlike the Public switched telephone system or a video routing matrix the single cable is shared by all the devices on the network so there are a set of rules to determine when a node can access the cable The technique used is referred to as Carrier Sense Multiple Access with Collision Detection CSMA CD Before transmitting a node listens to confirm that nobody else is transmitting then as it transmits it continues to monitor the cable in case another node started transmitting at the same time If two devices transmit simultaneously it is referred to as a collision and both devices have to stop immediately and wait a random amount of time before attempting to transmit again Several different manufacturers have adopted the low level Ethernet hardware and packet specifications and built their own networks on top of it Xerox XNS IBM SNA HP NS and DEC DECnet are all networking systems that allow users to share resources and files and can run over Ethernet In the area of Personal Computers 3com Corporation and Novell are supplying File server systems based on Ethernet Smal scale Office LAN s are mostly based on cheapernet which uses thin RG58 50 Q cable and BNC connectors in this case the coaxial cable is T eed directly onto the Ethernet Interface in the computer Higher level applications use better quality thick yellow cab
8. 6C 64 00 OA Data 2A 2B 49 8D Ethernet CRC 58 A60 Ethernet Manual FTP Implementation The following notes are intended to show the various states and messages of the Abekas FTP server Defaults As suggested in the ARPA FTP Paper these are the defaults assumed by A60 FTP ftp gt fport 20 ftp gt Iport 20 ftp gt passive FALSE ftp gt type ASCII ftp format NON_PRINT ftp byte_size 8 ftp gt mode STREAM ftp gt structure FILE Opening Message 220 Abekas A60 FTP Hostname 220 Abekas A60 FTP Commands and Responses The following are a list of all the commands supported and the possible responses Some of the responses are as the result of internal events such as ABORT where the data connection was closed mid transfer USER name 20 900 Username too long 230 User OK QUIT 221 Closing control connection PASV 227 Entering Passive Mode iii iii iii iii ppp ppp PORT error 901 Host Port spec not enough commas 200 PORT spec accepted host iii iii iii iii port nnn 59 TYPE error 901 TYPE bad args ASCII NON_PRINT 200 TYPE OK NON_PRINT TELNET cc 904 cant cope with that TYPE IMAGE 200 TYPE OK EBCDIC 904 can t cope with that TYPE LOCAL 8 200 TYPE OK else 504 cant cope with that TYPE MODE error 901 MODE bad arg STREAM 200 MODE OK BLOCK COMPRESSED 904 cant cope with that MODE STRU error 501 STRU bad arg FILE 200 STRU OK RECORD PAGE 904 ca
9. Protocols into layers is so that different protocols at the same level can be interchanged to provide the same function for the layers above Application OSI diagram The TCP IP protocols occupy the Transport and Network layers and can be applied to several lower level network architectures In this case the two lower levels that is the Physical fayer which defines the connectors and signal voltages and the Data link layer which defines the way data is passed between two pieces of equipment on the same local network are both defined by the IEEE 802 3 standard which in turn is based on the Xerox Ethernet V2 Another comparable Network standard is X 25 which is used for public packet switched services such as Tymnet Physical layer Ethernet was developed at Xerox PARC and is based on the concept of a baseband Carrier Sense Multiple Access with Collision Detection CSMA CD Abekas Transceivers The host computer will be coupled onto the Ethernet Coax by a device called a transceiver In some instances particularly in the case of Cheapernet the transceiver can be part of the Ethernet interface board in the host computer The Remote transceivers can be up to 50m away from the computer and typically come with a plug in module to allow either a spike tap N series or BNC connectors to interface to the cable Cheapernet uses thin 8058 50 0 coax and BNC style connectors rather than the high grade 10mm thick Yellow coax which pe
10. The A60 s Internet address is set via the Miscellaneous Menu on the contro panel To select the appropriate menu from the Norm Play home menu type 7 4 Menu Then enter the address in two halves as pairs of bytes separated by a dot eg 192 009 enter 200 005 enter Note that leading zeroes have to be included Setting the A60 Hostname The default A60 hostname is 460 which is fine unless you have more than one To make life easier it is possible to change the hostname on the A60 so that it is obvious which machine has been logged into Simply log in to the a60 using Telnet or rlogin and issue the hostname command to set a new name ourhost rlogin a60 Abekas A60 Remote Login a60 hostname fred 0 ourhost 27 Abekas Special notes for Yellow Pages Yellow Pages 28 If there is more than one Workstation connected to the network running NFS the chances are that the network service called the Yellow Pages will be running The Yellow Pages allow all the machines on the network to share the same configuration tables especially things like host names password and account information This simplifies the task of maintaining the system wide databases and means they only need to be updated in one place The existence of the Yellow Pages can be determined by typing the command Unix should respond with the name of the yp server ourhost ypwhich ypwhich ourhost is not running ypbind Say
11. and Reynolds IEEE 802 3 LAN Standards CSMA CD Access Method and Physical Specifications Oct 84 IEEE 65 Abekas Ethernet specs A LAN Data Link Layer and Physical Layer Specification Version 2 Nov 82 DEC Intel Xerox Other Background Reading Why is it that none of these texts were around when started on this project Byte Magazine July 87 Scientific American October 87 P 136 Networks for Advanced Computing Robert E Kahn Unix Papers for Unix Developers and Power Users p307 Ethernet A Unix LAN Charles Spurgeon The Waite Group Howard Sams amp Co 87 Handbook of Computer Communication Standards Vol 3 Department of Defense DOD Protocol Standards William Stallings 88 Internetworking with TCP IP Principles Protocols Architectures Dougias Comer Prentice Hall 88 66 A60 Ethernet Manual TCP IP Implementations The following machines are known to support TCP IP in some cases it vill depend on the operating system Digital Equipment Corp VAX and microVAX running ULTRIX or BSD Unix Hewlett Packard HP 9000 300 and 800 running HP UX Sun Microsystems Apollo Computer Pyramid Cray Symbolics Silicon Graphics Apple Computer Macintosh with Ethertalk 67 For the remainder there are add ons available from the following vendors Information based on entries in the DDN Protocol Implementations and Vendors Guide Excelan Intelligent Ethernet Controllers for VAX MicroVAX a
12. by cryptic one line commands rather than FTP which normally produces a secondary prompt and requires at least three commands to transfer one file The Abekas A60 The A60 can be viewed as a Video Server permitting all the rendering engines and computers in a graphics lab to share the ability to try out animation sequences and lay off rendered images without the prerol and lineup problems associated with single frame VTRs It is a powerful shareable resource that treats all the frames or fields on a disk as separate files that can be copied to or from the A60 The remote control provided across Ethernet is intended to be human readable in that the commands for playing or setting up segments are executed by typing PLAY or DEFSEG 0 20 1 30 a user sitting at a workstation can easily preview frames or animations without the need for a multiple control panels As an Ethernet device the A60 appears to be just another node that files can be transferred to in the same way they would be moved from one computer system to another there is no need for a separate VTR controller or special software Installation on Ethernet is just a question of the plugging the A60 into a Transceiver which is a smali box that provides an isolated interface to the Ethernet Coaxial Cable The System Manager then specifies an Internet address for the machine which has to be entered on the A60 contro panel The other computers on the network can then use thi
13. extern void play backwards extern void stopO extern void play_forwards also calls open_connection and close_connection as the window is opened and closed A60 Ethernet Manual open fonts font pf open usr lib fonts fixedwidthfonts screen r 12 bold pf_open usr lib fonts fixedwidthfonts screen b 12 create frame frame window create NULL FRAME FRAME LABEL demo A60 panel FRAME ICON amp a60 icon 0 a60 panel window create frame PANEL 0 play_back_button panel create item a60 panel PANEL BUTTON PANEL NOTIFY PROC play backwards PANEL LABEL IMAGE panel button image a60 panel lt lt 4 bold 0 stop button panel create item a60 panel PANEL BUTTON PANEL NOTIFY PROC stop PANEL 1 ABEL IMAGE panel button image a60 panel STOP 6 bold 0 play fwd button panel create 0 panel PANEL PANEL_NOTIFY_PROC play forwards PANEL LABEL IMAGE panel button image a60 panel gt gt 4 bold 0 window fit a60 panel window fit frame notify interpose event func frame catch closes NOTIFY open connectionO window main loop frame 53 54 this routine intercepts events and catches open and closes static Notify value catch closes frame event arg type Frame frame Event event Notify arg arg Notify event Lype type
14. generated by the A60 as packets arrive Debug Port The A60 Computer has a RS232 serial port on the front of the Card for debug It runs at 9600 baud and only sends data it does not receive it The connection is through the 5 pins on the fight hand end of the card The right most pin is pin 1 which is the transmit data from the A60 and the center pin pin 3 is ground Pin 2 would be receive if it did anything Debug Mask 1 gt 3 2 lt 2 3 7 A60 Debug RS232 DTE 25 way DType The hex weightings of the bits in the debug mask are as follows 2000 1000 800 400 200 100 ds FIN debug Turn on TCP debug as connection closes framestore addressing info TCP window info turns on TCP when packets are out of sequence Telnet IP TCP Application eg FTP or rsh Timeouts Ethernet Protocol Errors Network Errors Info messages Dump packets when IP debug is on as well Bughalt Debug level can be set through any of the login connections by using the debug command with a hex argument 41 Alternatively the debug level can be set from the contro panel menu 7 3 the equivalent debug setting in hex is given in parentheses 0 Debug off 1 Errors and TCP 11C 2 Errors TCP and Window 91C 3 Everything except Dump 1FC 4 Errors and Application 09C 5 Errors Teinet Sockets and Application 49C 6 Errors Teinet Sockets Application and TCP 59C default Errors and TCP 11C Note tha
15. goes 226 File Transfer OK 1244160 bytes sent in 29 40 seconds 41 Kbytes s ftp gt quit 221 Closing control connection Note that the FTP MPUT command is useful for transferring a whole set of files with similar names The file name on the host computer has to contain a frame number host Is pic 000 00 1 yuv pic002 yuv host ftp i a60 Connected to a60 220 Abekas A60 FTP a60 250 User OK ftp type image 200 TYPE OK ftp mput pic 200 PORT spec accepted host 192 9 200 6 port 1061 150 OK here goes 226 File Transfer OK 699840 bytes sent in 4 92 seconds 1 4e 02 Kbytes s 200 PORT spec accepted host 192 9 200 6 port 1062 150 OK here goes 226 File Transfer OK 699840 bytes sent in 4 92 seconds 1 4e 02 Kbytes s 200 PORT spec accepted host 192 9 200 6 port 1063 150 OK here goes 226 File Transfer OK 699840 bytes sent in 4 92 seconds 1 4e 02 Kbytes s ftp gt quit rcp A60 Ethernet Manual host rcp piccy a60 23 host rcp sym symb576 rgb a60 rgb rcp RGB Not a valid frame number host rcp sym symb576 rgb a60 24 rgb host rcp a60 24 rgb zzz Note that rcp from A60 to eg the same name in the current dir is supported host rcp a60 24 rgb host 4 Is rgb 024 rgb The A60 will generate a file in the form F 001 4 yuv The reverse case is not supported the A60 insists on having the filename specified explicitly host amp rcp symb576 rgb a60 rcp Not a valid frame
16. host with the required Internet address or a Gateway that can reach it will reply with a ARP reply packet supplying the requested Ethernet address Once the local host knows how to reach the A60 over Ethernet it can open up a TCP connection to the rshell port on the A60 The A60 which has been passively waiting for a connection to be made to its rshell port responds with an opening message and the rshell program passes the users name and the destination filename to the A60 Since the A60 does not support username validation passwords or accounting the transfer will proceed immediately with the transfer The A60 will seek to frame 37 and the data will be written to the framestore and displayed as it arrives When the transfer is complete the A60 will record the frame and close the connection A60 Ethernet Manual Layered Model The transfer outlined above used several program modules one was responsible for transmitting and receiving packets another assembled the incoming data into order and retranmitted unacknowleged outgoing packets At a higher level there was a seperate module that dealt with converting data formats Each of these modules has a well defined interface to the modules below wether it is passing a packet to the Ethernet module or reading and writing data to or from a TCP connection The ISO standards authority has proposed an Open Systems Interconnection model consisting of seven fayers The reason for dividing the
17. number By the same token directory copies or wildcards aren t accepted host rcp rgb a60 rcp A60 only supports single file transfers A third party copy from another host to the A60 does work host rcp otherhost frame yuv 260 45 it is implemented simply by invoking rcp on the otherhost via an rsh the reverse is not supported however since the rcp command is not supported by the A60 shell host rcp 2a60 22 rgb otherhost frame rgb rcp A60 cannot originate transfer no hostname table 19 Abekas Unix Script Hints 20 Here are some suggestions for ways to use Unix Command Files to shuffle files onto or off the A60 They all run under the C shell copy dir SMC Siggraph 87 copies all the frames with same root name eg pic in picOO1 yuv takes 5 params copydir rootname host baseframe note that frame numbers in filenames should have leading zeros or Is screws up the ordering set frame 3 set list Is 1 foreach i list rcp i 2 frame e frame end copy frames SMC NAB 88 takes two args the base frame number and the total number to transfer while count gt 0 rcp piccy frame 1 frame e frame count end A60 Ethernet Manual The following notes outline the commands available over the A60 s TCP IP Ethernet connection It assumes some knowledge of the operation of the A60 Refer to the A60 Operators Manual for more information on how the machine can be divided into segments a
18. of data however Transfer Times On a lightly loaded Ethernet with a host that supports 1024 byte TCP packets a 525 line YUV image should take about 7 seconds to transfer in either direction RGB images take approximately 25 seconds to transfer to the A60 and 33 seconds to read from the A60 Data Format Video data in the files transferred to and from the A60 is raw RGB or YUV data with no compression Run Length Coding or other structure There are 720 pixels per line and for a 525 line system there are 486 lines per frame 576 for 625 line systems The pixels are ordered in the same direction as the TV raster is scanned eg left to right and from the top down Three Bytes per pixel Red Green Blue 486 or 2 6 Lines 720 Pixels per Line RGB Files Refer to the A60 A64 Digital Video Interface Manual for more information on the format of the data and the size of the frame buffer Two Bytes per pixel Alternately U Y then V Y 486 or 576 Lines 720 Pixels per Line YUV Files Note that the A60 does not check the length of the file transferred but files longer than a frame in length can cause the Frame buffer addressing to wrap round and cause unpredictable effects A60 File Name Conventions The A60 expects a filename to contain the frame number and an optional extension yuv and rgb are currently supported yuv is the default The frame number can either be given as an absolute frame number in decimal or a time co
19. this copyright and permission notice appear on all copies and supporting documentation the name of M I T not be used in advertising or publicity pertaining to distribution of the program without specific prior permission and notice be given in supporting documentation that copying and distribution is by permission of M I T M 1 T makes no representations about the suitability of this software for any purpose It is provided as is without express or implied warranty 35 ea 1 05 1 06 1 0 fixes the slow mode that occasionally occurred on busy Nets provides extra debug for FIN states RARP and transmit failures At the higher level File transfers now restore the original display mode new commands Disable Enable Protect Unprotect and help fixes MIT PC problem Raw transfer ending mid packet Loop command with In Out is now trapped as illegal Close Wait state actually waits no longer sends RST Doesn t send ACK unless some data arrives fewer Resets Ether statistics eg lost packets available from rlogin Max TCP Segment Size now offered as 1460 bytes was 1024 Transfer From A60 in RGB for 1460 byte packets fixed upset rlogin rcp to 60 existent file handles error message correctly rcp originating from A60 rcp a60 0 host file now trapped property Odd byte packet start addresses now OK Tidied up Closing states FIN now retransmitted handles time wait state properly waits to catch any ACKs Lock
20. when the connection is opened packets are exchanged with the SYN flag set to indicate the initial sequence number The TCP header also includes a window to indicate to the other end how much buffer space is currently available This acts as a method of flow control since the transmitter should not continue if more than a windows worth of data remains unacknowledged The transmitting side of TCP is responsible for resending a data if it is not acknowledged within a timeout period There is a TCP Option that allows the maximum number of data bytes in a packet to be specified the default is 512 but some systems accept up to 1460 bytes this leaves 40 bytes for the TCP IP headers in the maximum sized ethernet packet of 1500 bytes TCP connections can be opened either Actively or Passively In the Active case the remote port and host address are fully specified whereas a Passive open will only specify the port number at the local end and wait for an incoming attempt to connect On closing the connection it is necessary for both sides to exchange and acknowledge packets with the FIN flag set UDP The User Datagram Protocol is a simple extension to IP which adds only a source and destination port number and a checksum The Datagram is a eo packet with neither guaranteed delivery nor special sequence TFTP and Sun Microsystems RPC and NFS are among the built on top of UDP Abekas Upper Levels For the TCP IP protoc
21. 0 local and foreign username vt 100 9600 0 term speed lt 0 user info validated Abekas A60 Remote Login n 60 User input is echoed character for character Both backspace and delete characters do the same thing eg gt b backspace c Nb b backspace space backspace The Sun appears to leave out the 9600 bit when the connection doesn t expect echo eg when invoked by rlogin host script Venix running on a PC sent n n instead of vt100 9600 A60 Ethernet Manual Bibliography Related Documents from Abekas Abekas A60 External Contro Protocol Manual Abekas A60 A64 Digital Video Manual Abekas A60 A64 SCSI Manual ARPA Publications DDN Network Information Center SRI International Room EJ291 333 Ravenswood Avenue Mento Park CA 94025 DDN Protocol Implementations and Vendors Guide A useful compendium of different TCP IP applications revised bi annually DDN Protocol Handbook Three Volumes Particular RFC s of interest RFC 826 Address Resolution Protocol Nov 82 David Plummer Symbolics RFC 903 Reverse Address Resolution Protocol June 84 Finlayson Mann Mogul Theimer Stanford University RFC 791 DARPA Internet Protocol Sept 81 J Postel Editor RFC 792 DARPA Internet Contro Message Protocol Sept 81 J Postel Editor RFC 793 DARPA Transmission Control Protocol J Postel Editor RFC 854 TELNET Protocol Specification May 83 Postel and Reynolds RFC 959 File Transfer Protocol Oct 85 Postel
22. Abekas digital disk recorder B Ethernet Manual A60 Ethernet Manual Rev 1 5 14 AUG 88 19987 1988 Abekas Video Systems Inc This manual describes the installation and use of the Abekas A60 Digital Disk Recorder as an Ethernet node supporting file transfer and remote login using some of the TCP IP family of protocols There is an application note describing some of the mechanisms behind the file transfers and the appendix lists information to allow the user to implement their own version of the file transfer routines Abekas Video Systems Inc 101 Galveston Drive Redwood City CA 94063 415 369 5111 FAX 415 369 4777 Easylink 62796899 Telex 592712 ABEKAS UD uucp Email allegra decwrl hplabs sun uunet pyramidiabekas a60mail Contents Introduction to Ethernet and TCP IP cccccccccsrcssssssccccscccsssscsscecccscecscsescecscessescensssecssensecuscucees 1 eE 1 TCP IB Ro Telnet and FIP RE eee 3 Unix COMMONS oro s deo Vos Wu ec 3 The DOK BS AOU MEER EET a 3 TCP IP Application u 4 Typical File OF eoo edite PR Ee EE Deus ovd agre oye evi 4 Laveted Model eee RE ONE Ya Reo adu Fer QUE Ee HERES 5 Physicalilav
23. ET SOCK_STREAM 0 0 perror demo socket exit 3 bzero char amp skt sizeof skt bcopy a60 h addr char amp skt sin_addr a60 gt h_length skt sin_family a60 gt h_addrtype skt sin_port rlogin_service gt s_port if connect sd char amp skt sizeof skt 0 perror demo connect exit 3 printf OK so farNn write sd login_str sizeofllogin_str close_connection close sd play_forwards write sd play_fwd_str strlen play_fwd_str play_backwards write sd play_back_str strien play_back_str stop write sd stop str strlen stop str 51 panel c 52 panel c quick lash up to show remote control of A60 from within a Suntools app using TCP IP see Sunview programmers guide for examples Copyright c 1987 Abekas Video Systems Inc x include lt suntool sunview h gt include suntool canvas gt include suntool panel h include lt stdio h gt include lt math h gt static short icon_imagel include a60 icon DEFINE IMAGE a60 icon icon image Frame frame Canvas canvas Panel a60 panel Panel play button stop button play back button Pixwin pw Pixfont font bold static Notify value catch closesQ calls five routines from demo c these first three are called when the appropriate button is pressed
24. Fie108 and TTE TEES 17 Field Dominanke mann 17 Write uu i MEISTE TE 17 up Pr rm 18 pu 19 Unix Script Hints M 20 A60 Remote Control over Ethernet cccccccccccssscscscccsrssecseccesssssscsscscscssscsssscsssenssasssscccsensesosesecs 21 Telnet eo rT X M 21 TTE 21 General Command Information cccccsssscscssscsssseccsccesecsesececccccscncccsnscncsscscsessessssessens 23 23 COMMENGS 4 22 sda sive ele 24 16127 10515 NER 27 Setting the A60 Internet Address ccecccccccsssssssssccscseccnscccsesecsccecsscacusccsesscccosescccunccsace 27 Setting the AGO Hostname NR 27 Special notes for Yellow Pages sscccccsssccsssssssscsscssescessccecccecessscvaccccccceacensscssssanccescesens 28 181109 Mem 28 gt 29 Implementation NOle8s 2 a 31 Ethernet 0 685 Ps 31 Address Resolution 31 m AA AE BAEENT E 32 V o 9 32
25. ackets The A60 sends ICMP protocol unreachable for services it doesn t support such as UDP Incoming ICMP information is not recognized Ought to support GGP simple echo reply but it s never been tested Don t think we support 4 2 BSD VAX Trailer Encapsulation whatever that is the Least Significant Byte of the Internet address is configured as zero the ethernet drivers will use the broadcast address I m not sure why we do this any more The A60 TCP initial sequence number is always zero A60 TCP does not check security or precedence level of packets Since the A60 is not really a shareable resource it only supports one connection per socket Any subsequent connection attempts will be ignored When a TCP packet is not acknowledged the A60 will resend the packet up to twenty times with increasingly larger intervals before aborting the connection TCP Seg size option of 1460 is written out and the A60 responds appropriately by honoring incoming SEG SIZE option up to 1460 The default segment size is 512 PSH flag is now set for each packet sent Pyramid systems seem really sensitive to this A60 Ethernet Manual Telnet None of the Telnet options are supported The A60 will just respond courteously with the appropriate negative response eg WILL DONT WONT gt DONT DO gt WONT etc Ought to issue the Telnet Option Suppress go ahead especially since we don t issue Go Aheads but don t as yet A60 will ac
26. c lists the undocumented commands grab source grabs a single frame by unfreezing the video input for exactly two fields This allows external compositing with the A60 output normally when selecting video in this case the machine would just feedback source in this case is 1 or 2 for inputs 1 and 2 defaults to one A60 Ethernet Manual These notes apply in particular to SunOS there may be local variations Installation should be simply a matter of adding the Internet address chosen for the A60 to the file etc hosts and then entering this address on the A60 contro panel For these changes to the host machine you will almost certainly require superuser privilege This is probably the point to contact your local Unix Guru etc hosts Edit the etc hosts file note that root normally has a as a prompt In the following notes ourhost is a fictitious example hostname ourhost vi etc hosts Entries in the hosts file have the following format 192 9 200 5 Everything to the right of is ignored as a comment Lines consist of two more fields separated by whitespace tabs or spaces The first field on a line is the internet address of the host Following normal convention it is expressed as four decimal numbers separated by dots The second field on a line is the hostname Any subsequent names on the line are aliases for the same machine normally local abbreviations or nicknames Setting the A60 Internet Address
27. cept CR LF or CRLF as a line terminator The HP 9000 300 workstation has problems with A60 Teinet lt CR gt doesn t locally echo as lt CRLF gt use LF instead Symbolics systems seem to think that remote echo is a default option for Telnet it isn t in the book we have FTP We attempt to minimize the password and accounting formalities by replying with a User OK after just a user name Some applications at the other end still insist on providing a name and password however facilities such as the Unix netrc file can smooth the FTP login sequence The A60 isn t a real computer and there just wasn t space to keep track of names and access permissions Third party FTP transfers controlled from TN different from the data connection have never been tested When using FTP most applications require that TYPE IMAGE is specified in order to stop the focal host expanding Carriage Returns into Carriage Return Line Feed sequences Although these aren t valid CCIR 601 video values so they shouldn t appear in the file it still takes the host time to filter the data Hangs up at the moment if the Remote client restarts and our end is still open It s OK if we restart with the other end still up since the next packet sent from the other end will most likely be out of sequence and illicit a reset from our end 33 A60 rcp can t cope with wildcard transfers eg the command rcp rgb a60 will return an error message flogi
28. d control The control is achieved using a command and Response Dialog which may or may not be visible to the user Commands are of the form USER Simon and STOR pic rgb FTP responses are preceded by a three digit code which allows a machine to assess the required action A60 Ethernet Manual Some of the meanings are listed below is a Positive preliminary reply 2xx is a Positive completion reply 5xx is a Permanent negative completion reply x0x is a Syntax error x2x refers to a connection x5x refers to the file system Example FTP transfer In the following example each line shows a step in the transfer the arrow indicates the direction of the message is from the host to the A60 and the carriage return and line feed characters are shown in language notation Nr and n open TCP connection to port 21 on the A60 1 220 Abekas A60 FTP a60 USER simon r n 230 User OK PORT 192 9 200 1 30 244 r n 200 PORT spec accepted host 192 9 200 1 port 7924 gt STOR 407 rgb r n Active open from A60 end port 20 to 192 9 200 1 port 7924 150 OK here goes Data Transferred far end closes data connection when done 226 File Transfer OK QUIT r n 221 Closing control connection TFTP The Trivial File Transfer Protocol is built on top of UDP and provides an easy to implement ile transfer Data is transferred in 512 byte blocks each data packet carrying a block number Each block has to b
29. de The A60 starts at the end of the filename and works back so you can include all the directory paths you want they are all ignored rcp thing400 a60 users simon piccys thing400 yuv parses OK as 400 yuv Be careful that filenames don t have an before the frame number since this has the special significance explained below A60 Ethernet Manual Fields and Frames Video can be transferred as Frames or Fields A frame is twice as long as a field and the lines are interleaved in the same way as they appear on the display A field transfer is indicated by an F immediately preceding the frame number The first field of a frame will be implied by default To access to the second field the frame number must have a appended to it The frame number can also be specified in timecode in which case seconds and frames are separated by dots for the first field and colons for the second rcp mypic yuv a60 590 places the frame mypic at 590 rcp myfield yuv a60 f590 rcp mypic yuv a60 f18 25 records the file as the second field of frame 590 18 25 in timecode on 525 line systems Field Dominance The diagram below show the difference between a frame that starts with a field and a field 2 The example is for 525 line systems since in 625 the upper field eg the one with the half l ne at the top is actually field 1 00 00 00 00 Eod 00 01 00 02 SUN 00 03 00 03 S
30. deo Systems Inc include lt stdio h gt include netdb h include errno h include lt sys types h gt include sys socket h include netinet in h char login_str Osimon Osimon char command_str rcp t O rgb this ought to be variable char file_str C0666 1049760 mypiccy n different length for yuv char close_str int sd global socket descriptor main argc argv int arge char argv int i FILE piccy char line 720 3 open_connection piccy fopen argvi 1 r for iz0 14486 i fread line 720 3 1 piccy write sd line 720 3 close close connection char tmp_str 20 int n write sd close_str sizeof close str 1 n read sd tmp str 20 close sd A60 Ethernet Manual open connection struct sockaddr_in skt struct servent rlogin_service struct hostent a60 int Iport char c tmp str 80 str 80 int n if rlogin service getservbyname shell tcp NULL fprintf stderr demo tcp unknown service n exit 1 if a60 gethostbyname a60 NULL fprintf stderr demo a60 unknown host n 1 bzero char amp skt sizeof skt bcopy a60 gt h_addr char amp skt sin_addr a60 gt h_length skt sin_addr s_addr INADDR_ANY if sd socket AF_INET SOCK STREAM 0 lt 0 pe
31. e acknowledged before the next one can be transmitted TFTP is used for booting diskless hosts on a local network and exchanging mail 14 As is the case with most Unix applications the implementation of is elegantly minimal Most of the handshaking is achieved by the transmission of a single nuli byte Most of the commands use a single TCP connection although there is provision for a standard error connection In the following example 70 indicates that a nuli zero byte is sent rcp pic400 rgb a60 312 rgb NO no standard error local and remote username NO confirm user info validated rcp t 312 rgb 0 the command NO command OK C0666 1049760 pic400 rgbNn Access flags length original name NO 1049760 bytes of data 0 NO These transfers are listed in more detail in the appendix A60 Ethernet Manual File Transfer General Information RGB Conversion The A60 has the capability to convert raw RGB files to YUV and back again The arithmetic is done 32 bit fixed point using the on board Multiplier Accumulator Chip Reciprocal Anti Aliasing and Interpolation filters are used to minimize generation loss Some slight degradation will be visible on the first pass into and out of the machine Once the image has been bandwidth limited to YUV space it does not degrade further on successive passes The conversion process does slow up the transfer
32. ection is only referenced by tcb tcp control block number TCP 4 send 0 Seq 1 Ack 33741058 Win 450 PSH ACK IP Debug ipdemux got pkt 120 prot 6 from 192 9 200 1 On the input side IP prints a message per packet with the length and the protocol number Relevant protocol numbers are as follows TCP 6 ICMP 1 GGP 3 inwrite pkt 25 prot 6 to 192 9 200 1 route 192 9 200 1 Ethernet Debug Ethernet level debug takes the following form ET_SEND p 45 192 9 200 1 ET_DEMUX got pkt 60 buf O type IP ET free buf 0 Recognized packet types IP 0800 ARP 0806 RARP 8035 43 44 A ping should look like this First there is an ARP request for the A60 s ethernet address then an ICMP echo request DEMUX got pkt 60 type ARP SEND gt 08 00 20 01 FF 9C et free buff 4 ET DEMUX got pkt 98 buf 5 type IP ipdemux got pkt 64 prot 1 from 192 9 200 1 ICMP p 64 from 192 2 200 1 ICMP echo reply to 192 2 200 1 inwrite pkt 64 prot 1 to 192 9 200 1 route 192 9 200 1 5 p 64 gt 192 9 200 1 Some packets will be discarded ARP requests that are not intended for this machine and broadcast packets from unsupported protocols such as XNS A60 Ethernet Manual Glossary ARP Address Resolution Protocol used to obtain Internet to Ethernet address mappings when they are needed rather than maintain a static list on each host ARPA Advance Research Projects Agency US Government agency responsib
33. ed out play commands during Transfer NB EM still active No longer left in freeze after record command Buffer wrap around problem FTP too many commas error 11 also occasionally missed frame in the middle of iong Raw ends before all up to date esp from PC Record command now shows next frame rather than In point Test Patterns drawn a line higher in the store 1st line was black debug command with no param returns current setting RGB conversion doesn t blow up with values less than 16 SYN s rejected on open connections SYN s ignored during Time Wait state Window less than zero problem fixed FTP waits longer for its data connection Chunks and reassembly cleared between connections 1 08 36 fixed Address error if RGB read allowed to have odd length Retry times are now exponential eg wait twice as ong each time Window and retry time can now be tweaked from debug TCP debug per tcb includes of times it gets ahead A60 Ethernet Manual 1 09 Reset over riogin clears framestore lock NOOP FTP command fixed TYPE L8 accepted in FTP 1 10 Heip for undocumented commands Help parameters can be shortened interpolator turned off if Bars are drawn 1 11 fixed bug in bug fix for non null sent by rcp added PSH to all packets to keep Pyramid happy New commands for paint systems input freeze and recrel 1 12 fixes crash when offered window is greater than 1460 again 1 13 fixes a couple of SCSI p
34. ent locking up the network If the output is active for more than 1 10 second the Transceiver should latch up and prevent further transmissions until the Transmit signal is inactive for at least 1 4 second Jam A collision signal generated by a repeater so that the cable segments on both sides of it are aware that a collision has occurred Heartbeat See SQE A60 Ethernet Manual Host A computer that is a node on a network Hestaame The name by which a particular machine is known at the user interface level normally associated with a Network address MAU Medium Attachment Unit The official IEEE name for what mortais refer to as a Transceiver NFS Network File System Developed by Sun Microsystems NIC Network Information Center The central repository for all information regarding the development of the ARPAnet OSI Layered Medel The much vaunted abstract model for the seven layer hierarchy of network protocols issued by ISO the International standards body Still under development at the higher layers Piag Program that uses the ICMP Echo Request facility to verify the connections between two machines Note that this only verifies correct operation up to and including the Network layer or Internet Protocol Port Number An addressing scheme within a host computer that allows more than one simultaneous connection to that computer Repeaters Repeaters interconnect or buffer two sections of the same Network with very litt
35. er UE FUR 5 C OLY OLS m MT 6 Different Ethernet Standards ccsccccscsssscsscssssssssssssscsssscsssscssecsessscsserssesscssccsecs 6 SDE aE N O EO 7 Data Link LAVO EE T T TIE 7 Ethern t Addresse3 aasin 7 Network iP VU essen 7 p ec du teed 7 internet 0 oor Eni E Fave Doss ERE VF a Ta Fo ER ERR RF RR a eR NN RE To PEE TR OR eue E 8 a 2 MEIN 8 T I 9 Y T T 9 Iu nior aerei css d 9 Transport LaVBE reato eu PUDE 10 ICP Macc T 10 UDP anne 11 Upper 12 NER TRETEN 12 T ____ 12 Example FTP transfer essen 13 X 13 ER 14 File Transfer Fn 15 General Information oor Roca __________ 15 RGB Conversi iei urne cO LO EHE e QVO A ____ _ 15 Translor TIMER Rm 15 ccu et 15 A60 File Name Conventions cccccccccccccccccccscsccccccceccsecccscssesscssccccssssncreccssseeees 16
36. er is also responsible for detecting collisions UNII is a Trademark of AT amp T Bell Laboratories Available in two main flavors at the time of writing BSD 4 2 and ATT system V others based on the PC platform include SCO Microport and Xenix The Berkeley Software Distribution BSD version is the one that first supported the ARPA protocols most popular Unix Systems eg SunOS HP UX and DEC Ultrix are a mixture of the Berkeley and AT amp T UDP stands for the User Datagram Protocol a datagram is a stand alone packet with no can be transmitted over the network with no implied sequence or guarantee of delivery UDP is an alternative to TCP at the Transport Level NFS and Yellow Pages are built on top of it 1 25 Public Wide Area Packet Switched Network Standard Yellow Pages The Yellow Pages is a network service that provides network wide Password and system information from a single database Written by Sun Microsystems but available on many systems YUV the Native data format of the A60 an alternative encoding to RGB for component video and one that is more suited to the limited bandwidth of Broadcast TV The Y channel is luminance and the U and V are color difference components B Y and R Y respectively The color difference signals are normally stored at half the sampling frequency of the Luminance A60 Ethernet Manual Example Programs The following programs are examples of remote control and file transfer from within a p
37. es in Europe When packets are passing across several networks through gateways which provide an interface from one type of network to another there is more chance of a packet getting lost There s no guarantee that all that packets will take the same route to the destination this is possible since each packet carries separate addressing information It is up to the gateways to decide which is the most efficient route If during the life of the connection one of the intervening gateways or networks goes down the TCP IP protocol is robust enough to be able to replace any unacknowledged fost data by retransmission assuming an alternative route can be found A60 Ethernet Manual Telnet and FTP The A60 supports file transfer and remote control built on top of the guaranteed delivery TCP connections Remote control is achieved by allowing the remote user to login as if the A60 were another computer and type commands interactively There are two alternatives for each Firstly the official ARPA file transfer and remote login utilities called FTP File Transfer Protocol and Telnet These are specifically intended to work between different Computer architectures and Operating Systems Unix r Commands The second alternative is the native Unix utilities rcp remote copy r ogin remote legia and remote shell These will be popular with Unix users since they offer less verbose user interface file transfers are achieved
38. f Ethernet Address 38 Has the Ethernet Address changed 2 In some cases where the software or the computer card is changed the Ethernet address might be different Some systems retain hostname ethernet address tables thatneed to be flushed in the unlikely event that the address changes see the fast paragraph of the preceeding section on Intasileing on a Unix network etc ethers A60 Ethernet Manual Internet Address Is the Internet Address set up correctly Assuming you have access toa ping program and that the Internet address has been entered on the Control panel Note that ping is sometimes hidden away in etc or usr etc The Internet address should have the same network address as the rest of the hosts on the same local net The network address s the top byte of the internet address if the top byte is fess than 128 the top two bytes if the top byte is greater or equal to 128 and fess than 192 or the top three bytes if the top byte is greater or equal to 192 If the Network part of the address is not the same the remote host will think the A60 is on a different network Most pings will have to start by using ARP to find the Ethernet Address of the A60 There are two LEDs on the front of the computer card CSEN shows ethernet carrier sense and should flicker with any network activity DMA shows the Ethernet Controller is driving the 68000 bus indicating that packets are being transmitted or received by the A60 If P
39. g Gateways ARP The Address Resolution Protocol uses the Ethernet Broadcast Mechanism to allow a host to resolve Internet to Ethernet address mappings by asking ali the hosts on the local network if any of them claim to be the required Internet address If the hosts support ARP they will decode the packet it contains both the Internet and Ethernet Addresses of the local host and the Internet address of the host it is trying to reach Only the requested host or a Gateway that can reach it on another network reply directly to the requesting machine RARP The Reverse Address Resolution Protocol allows an Ethernet host to determine its own Internet Address by broadcasting a request to the net Abekas Transport Layer The fourth OSI fayer is the Transport Layer which is concerned with creating and maintaining logical connections between individual processes on different hosts kii e Hune 5 89890888 AS AAR 6 UP ___ d i ud i oes Type j 1 Ether net y y ini i iru ID Ht DRHEHAM ALERT HAE E m EE ipn F ui Hinr Hi EIE gt Typical Data Packet 886855 The transport layer adds a source and destination port number to
40. g for 4096 separate hosts on the one network A class B address will have a first byte in the range 128 to 191 and in this case the lower two bytes form the local address Class C addresses will have first byte greater than 191 only the last byte identifies the individual machine or internet node Internet addresses are intended to be more wide ranging than the native addressing scheme for the the local network it is possible to connect to an Internet host across several different types of network eg Local Area Ethernet long haul X 25 packet switched services and Local area Token ring networks ICMP Internet Control Message Protocol is almost an integral part of IP It is intended to handle error reporting from Gateways to hosts or hosts to hosts It gives the originating host more information about the reason a packet has been rejected or cannot be delivered ICMP also provides an echo system used by ping programs to help isolate inter network problems A60 Ethernet Manual A Selection of the ICMP Messages Echo Request Echo reply Redirect Use alternative route Time Exceeded Packet died of old age Parameter problem Something wrong with the IP Header Destination Unreachable either Network Host Protocol Port GGP The Gateway to Gateway Protocol Handles communication between Gateways for control purposes It allows them to exchange routing information and keep up to date on the availability of neighborin
41. host cat script clearseg defseg 100 200 pause defseg 500 400 pause loopseg 1 2 host rsh a60 script host rlogin a60 a60 w 165 608 w 174 a60 w a60 plays a6058 w 307 Note that out point for a segment is not inclusive eg defseg 100 200 plays frames 100 to 199 Note the following case where information can be interpreted by a shell script Record relative Record a single frame of input video at the current location set frame rsh a60 where rsh a60 record input frame A60 Ethernet Manual General Command Information Upper or lower case allowed Shorter forms of commands given here can be given Parameters separated by spaces Only one command per line Note that segments are numbered from one Parameters listed in brackets are optional Be warned that in the case of ambiguity the earlier command in this list is executed Parameters speed 10 9 10 9 limits 30 for 525 line systems 25 for 625 resolves three decimal places eg 11 50 5 5 30 7 125 are all legal speeds frame If 1 1 0 99 0 99 accepts absolute frame numbers with trailing to indicate the second field or timecode with for field or 2 field mode or auto frame is not changed eg 1 3 01 1 00 24 1231 are all valid seg 1 100 segments can be numbered from 1 100 The segment number follows the order in which the segments were defined source any of the following is permissible as a record source it shou
42. ing fails more than about percent of the time unless the network is unusually heavily loaded this sounds like a noise or grounding problem The A60 does suffer spurious collisions on transmit if the Transceiver cable is improperly shielded 68000 Is the Motorola 68000 that controls the A60 Ethernet Hardware running 2 If the 68000 has hung the A60 will be unable to write test patterns into the store but the disk transport functions may appear to work OK Press the Reset Switch on the Computer card at the right hand side near the front Check for bent pins on the 68000 PROMs 1C 7C Disks Are the disks up If communications appear to be OK but the A60 won t record or play the disks might be spun down there is a toggle switch on the front of the Computer card which should be to the right for normal operation 1805 Has one of the 2805 crashed the HLC LLC goes down the A60 will not respond to commands from the control panel The Status display may be showing an illegal timecode or may be corrupted Operation of the Z80 s is closely coupled to the incoming reference sync If this is removed or replugged they may become confused If the HLC is not running the whole machine hangs up and all the lights on the control panel stay on If the Reset button fails to correct this condition try clearing the Non Volatile RAM by changing the position of the first DIP switch at 18k on the computer card 39 Abekas Reference Syncs I
43. ioning correctly Ethernet V1 does not provide for SQE Data Link Layer The Data Link layer provides for source and destination addresses and a trailing CRC allows the integrity of the whole packet to be checked Ethernet and IEEE specifications differ in a few minor respects The IEEE spec states that the field immediately following the source address is an optional length however the Ethernet receiving hardware is capable of determining the packet length by other means The original Xerox Ethernet spec defines this as a type field which is used to resolve the next protocol above in the hierarchy The types used for the ARPA family of protocols are intentionally chosen to be illegal lengths eg larger than the maximum permissible so as to remove any confusion between the IEEE and Xerox implementation of Ethernet Ethernet Addresses Ethernet addresses are six bytes conventionally written as six hex numbers separated by colons Ethernet addresses are intended to be unique for any piece of equipment that conforms to the IEEE 802 3 standard Abekas Equipment will be in the range 00 00 76 0C XX XX Using the Ethernet Broadcast packet mechanism it is possible for the local host to send a packet to all the devices on the local network rather than to one specific address This address is FF FFFFFFEFFEFF Network Layer The Network Layer provides a packet delivery system between two hosts IP The Internet Protocol adds to a packet the informa
44. ld only be necessary to type the initial letter of each option bars pattern pattern num input Digital Video in 1 aux Digital Video in 2 drame a frame number pattera num from 0 100 Bars 95 Bars 75 Bars Lin Ramp Mod Ramp 10 Step X Hatch 2T pulse Pluge Muitiburst Bow Tie Digital test 100 Combo 95 Combo 75 Combo display mode field or frame 23 Abekas Commands 24 play speed defaults to 1 0 play from the current position step stop loop or play goto frame defaults to 0 goto the given field or frame jeg leffset defaults to relative goto field or frame offset is determined by the current display mode loop cin eut speed loop play the specified segment defseg in out speed pause define the next segment from in to out with optional speed speed defaults to 1 0 pause can be typed in full or just p goseg seg defaults to 1 goto the in point of the given segment playseg speed play thru the segment list from the current position or alternatively resume playing after a pause loopseg in out speed loop play the specified segments clearseg clear the segment list macro macro aumber execute the given macro quit close down the connection A60 Ethernet Manual hostname set the hostname returned in the prompts default a60 makes it easier to use two machines where where returns the current frame record
45. le intelligent signal processing RFC Request For Comment the main instrument of the ARPA Community a sort of Network Memo Often quoted in references e g RFC 793 is the latest description of TCP They are available from the Network Information Center see NIC above Server A host or node on the network that provides a service eg a File Server provides a File system for Diskless nodes SQE m Signal Quality Error some Ethernet Transceivers generate a colfision signal immediately after each transmission This permits the Ethernet Interface to verify that its collision detection circuitry is functioning correctly 47 48 Secket A socket is an abstraction in BSD Unix for the interprocess communications primitive the known as the pipe A socket can be opened in much the same way as a file would be opened Telnet ARPA remote terminal login program TFTP Trivial File Transfer Protocol built on UDP simpte to implement 1 5 and 10BASE2 IEEE names for Ethernet and Cheapernet respectively abbreviated from 10MHz Baseband 500m and 200m maximum length watch for a twisted pair spec Thia LAN or Thin net see Cheapernet Transceiver The box which attaches the Host computers Ethernet Interface to the cable The best ones use a spike arrangement to non intrusively attach to the cable eg without cutting it The transmit and receive signals are coupled onto the cable through isolating transformers The transceiv
46. le and external transceivers which can attach to the cable with a spike like tap TCP IP The TCP IP protocol family is emerging as a useful common standard for network interconnection The strength of TCP IP has been that it is not tied to any particular manufacturer it is the result of extensive research since the 70 s by the Advanced Research Projects Agency ARPA community With backing from the DOD the emphasis for these protocols has been to interconnect different types of computers running different operating systems TCP IP is now available as an add on to most computer systems either in the form of an interface board with built in software such as the Excelan Ethernet Controllers as an extra software package running along side a native Ethernet implementation The Bibliography for this manual lists some of the companies offering TCP IP packages One reason for the spread of TCP IP amongst the Computer Graphics Community has been its inclusion in the Berkeley Versions of the UNIX operating system referred to as 4 2 BSD UNIX as opposed to the AT amp T Unix System V most graphics engines and the Workstations that controi them use Unix as it is a popular operating system for software development TCP and IP are acronyms for Transmission Control Protocol and Inter network Protocol just two of the layers in the suite of communications protocols that are required to allow transfer of data from one computer to another
47. le for developing TCP IP family of protocols AUI Attachment Unit Interface the long way of saying transceiver cable Normally limited to 50 meters and carries twisted pair differential signals for transmit receive and collision detection The AUI cable also carries 12v power for the Transceiver Bridge Bridges are generally connections between Networks of the same type at the Data Link Layer Breadcast Packet an Ethernet packet carrying the address FF FFFFFFFFFF which will be received by all the hosts on the network CCIR 601 This is the Standard for digital video drawn up by the international committee it is also referred to as SMPTE RP125 and EBU 3246 E Cheaper nct an alternative form of ethernet that uses thin RG58 50 Ohm cable with BNC connectors and pieces at the transceivers rather than that normally used for Ethernet This cable suffers from greater loss and the the cable run is typically limited to 185 m In all other respects it is electrically compatible with Normal Ethernet Client The consuming user end of a client server relationship Cennection ZEE the link between two specific ports on two Internet Hosts analogous to a telephone cal being set up between two phones on a network CRC Cyclic Redundancy Check a sort of serial check sum that assures the integrity of a serial data stream by using some sort of polynomial feedback basically a shift register and a few exclusive or gates CSMA CD Co
48. llision Sense Multiple Access with Collision Detection Describes the mechanism that allows several devices to share the single Ethernet cable 45 46 Domain Names A name addressing scheme that uses a hierarchy of domain names to describe the address of a remote computer in a similar way to a mailing address eg simonemaster abekas COM Ethernet Vi and V2 The original Ethernet standard was developed by Xerox and published jointly with DEC and Intel Ethernet Address A 48 bit address conventionally written as 6 hex bytes separated by colons The IEEE hopes that there are enough addresses for every piece of ethernet equipment in the universe to have its own unique address Typically vendors ship equipment with the Ethernet address contained in a small bipolar ROM Fragments Sub divisions of Internet packets sometimes necessary if different networks have different maximum packet lengths FTP File Transfer Protocol 4 2 2 The Ratio of the sampling frequencies for components in Digital Video Four Luminance samples for each two of the color difference signals Gateway Gateways allow interconnection of different Networks at the Network layer IEEE 892 3 The IEEE standard for CSMA CD Networks forms part of the 802 x family of standards for Local Area Network Interfaces and Protocols Internet Address A Four byte number representing the address of a host on the Internet Jabber A condition detected by a Transceiver to prev
49. n can be terminated by control D or control C In rlogin either ASCII back space or delete have the same effect fCp actually uses the rsh port General 34 Segments that have been set record lockout from the A60 control Panel appear to the file transfer utilities as write protected files Remote Control through the Login utilities is locked out while a file transfer is in progress When the A60 SCSI Port is in use the Ethernet services are not available The A60 is still liable to hang up if the remote end of a connection goes away without any warning it keeps the connection open and refuses any further attempts to connect to that port even from the same host At the moment the only way round this is to issue a reset command over rsh rlogin or Teinet assuming they are not all hung at once The reset command will clear out all existing connections Filenames or frame numbers can have all sorts of directory junk on them the parser works back from the far end of the name eg optional extension plus for second field frame number f for field A60 Ethernet Manual Copyright Notice The following notice has to be included because Abekas TCP IP is based on a Public Domain program called PC IP originally written by John Romkey and others at MIT o 1984 1985 Massachusetts Institute of Technology Permission to use copy modify and distribute this program for any purpose and without fee is hereby granted provided that
50. nd the limits on play speed etc Remote commands can be invoked in three ways Telnet Rsh and Rlogin The following examples assume the commands are given on a UNIX machine with the prompt host The A60 has several operating modes particularly Segment Normal play and Loop Mode most of the commands given here will work with the machine in any state however they can leave the machine in a different state Telnet From Unix type host telnet a60 Abekas A60 Telnet a60 gt play a60 gt quit rsh rlogin rsh allows a single command to be executed on the remote machine for instance host rsh a60 play 0 5 Both Rsh and Riogin offer an interactive login either host rsh a60 or host rlogin a60 Abekas A60 Remote Login a60 play a605 quit the login can also be terminated by D or C 21 22 Note that it is also possible to redirect a file to the remote shell even though this is not strictly legal Unix Syntax To achieve the same effect between two Unix machines you actually have to type rsh rhost csh script host cat script clearseg defseg 100 200 defseg 300 400 loopseg 1 2 host rsh a60 script This provides an easy way to keep track of the segment list from the host computer since it is not possible to read back the segment list from the A60 Feedback is limited to the where command but this should be enough to indicate that the A60 has reached the end of a segment with a pause in it
51. nd IBM PC TCP IP software support for RSX 11 VMS Unix System V and MS DOS 2180 Fortune Drive San Jose CA 95131 408 434 2300 Wollongong TCP IP software for HP 9000 series 500 VAX IBM PC 1129 San Antonio Road Palo Alto 94303 415 962 7200 3com Corporation Ethernet Interfaces for the IBM PC 1365 Shorebird Way PO Box 7390 Mountain View CA 94039 415 961 9602 FTP Software TCP IP software for the IBM PC PO Box 150 Kendal Square Branch Boston MA 02142 617 864 1711 68 Abekas Video Systems Inc A Carlton Company Abekas Video Systems Inc 101 Galveston Drive Redwood City 5 CA 94063 Tel 415 369 5111 Telex 592712 Fax 415 369 4777
52. nt cope with that STRU A60 Ethernet Manual RETR 2 901 arg count name parse 990 Bad File name data conn 125 Data Connection already open 150 OK here goes UNOPEN 425 Cant open Data Connection ABORT 426 Connection Closed Transfer Aborted LRESET 426 Connection Closed Local Reset FRESET 426 Connection Closed Foreign Reset NORMAL 226 File Transfer OK STOR name parse 550 Bad File name data conn 125 Data Connection already open 150 OK here goes UNOPEN 425 Can t open Data Connection ABORT 426 Connection Closed Transfer Aborted LRESET 426 Connection Closed Local Reset FRESET 426 Connection Closed Foreign Reset NORMAL 226 File Transfer OK NOOP 200 NOOP OK else 202 Command not implemented 61 Abekas File Names The A60 is not case sensitive The correct syntax for a filename on the A60 is as follows optional leading slash or directory path ignored F to indicate a field transfer optional timecode 19 20 frame at 19 seconds 20 frames or 19 20 second field or 590 frame 590 or 590 frame 590 second field extension RGB or YUV optional defaults to YUV rlogin Implementation 62 In the following section indicates a null byte 10017 indicates a byte of value An indicates ASCII Line Feed indicates ASCII Carriage Return b indicates ASCII Back Space open connection to port 513 0 no standard error connection simon Osimon
53. ols the top three OSI reference layers tend to be merged into one program at the highest Application layer The OSI model also provides for a Session layer which handles user validation and mapping host names to network addresses and a Presentation Layer which handles machine differences like byte swapping and terminal standardization CD Gu CD GD Gd EB CD Qc DI terne TCP IP Family Tree Telnet FTP Telnet is a remote login program based on the concept of a Virtual Terminal The Virtual Terminal has a set of default conditions that can be changed by negotiation and mutual agreement between the local and remote host For instance echoing is done locally by default and the local host is expected to buffer lines of text until lt Return gt is pressed The Telnet connection has an escape mechanism where hex FF is the escape character An FF occurring in the data stream is transmitted as FF FF The escape character precedes an option negotiation which contains a code to indicate WILL WON T DO or DONT and the particular option code Options include the ability to turn off echo and set various terminal attributes such as line length Before an option will be implemented on both sides they have to positively agree to do it The FF escape sequence is also used to implement out of band signals such as Abort Output Interrupt Process and Erase The File Transfer Protocol uses a Telnet connection for User authentication an
54. omputer card 60 8 have an officially allocated Ethernet address range 00 00 76 60 XX XX the last two bytes being determined by the Computer Card Serial Number The Ethernet address of a particular card should be engraved on the left hand side at the front of the card Note that if the Computer card is swapped the Ethernet Address is likely to be different The A60 is compatible with IEEE 802 3 or 10 Mbit s Ethernet V2 the only difference is the transceiver cable grounding arrangements The A60 doesn t care if the transceivers generate SQE it s just ignored however in practice it has been found that some transceiver cable combinations have produced problems that went away when SQE was disabled Address Resolution The A60 supports both the Address Resolution Protocol ARP and Reverse ARP The A60 vill attempt to use RARP in the event that the machines Internet address is set to 0 0 0 0 and a power on reset occurs twice This will either be the result of a really cold start eg the Non Volatile RAM in the machine has been trashed or if the address is set to 0 0 0 0 from the control panel and the Computer Reset button is pressed twice RARP vili only work if someone out there is serving up Ethernet Internet address mappings such as the rarpdaemon on a Sun which refers to the etc ethers file If there is no reply the Internet address will remain at zero 31 TCP 32 The A60 IP is not capable of re assembling fragmented p
55. rmits the non intrusive vampire tap transceivers to be spiked into it and removed without having to take the network down The thick coax can be used for networks up 100 nodes on 500m of cable whereas Cheapernet is limited to 30 nodes on 185m of cable Only two repeaters are allowed on a local network because of the propagation delays through them The transceivers should be placed at multiples of 2 5metres on the cable Different Ethernet Standards There are three different Ethernet standards Ethernet V1 V2 and the Newer IEEE 802 3 standard The are electrical differences between the different standards mainly concerning the grounding requirements for the transceiver For Ethernet V1 and V2 the connector shell cable shield and pin one of the connector are all connected together whereas for IEEE 802 3 the cable shield is separate from pin 1 ground The grounding should be achieved at the host end of the transceiver cable Outer Shield 1 Collision 2 Transmit 3 9 Collision 10 Transmit 12 Receive Receive 5 13 Power 12V Power Return 6 e O Transceiver AUI cable pinout A60 Ethernet Manual SQE Some transceivers support SQE or Signal Quality Error sometimes called heartbeat in which case they will return a collision in the gap at the end of every transmission from the host This provides a way of assuring that the collision detection circuitry in the host interface is funct
56. roblems extended commands didn t expect the correct number of command bytes undid an old bodge to support Kennedy s w 241 002 and greater 1 14 fixes another SCSI problems hangups with a Sun 3 260 now have SCSI debug select debug level 9 also fixes slow mode ethernet finally fixed those buffers and interrupts for good 37 Troubleshooting Some of these things are probably covered elesewhere in the user manual but if like me you only turn to the manuals when something appears to be broken this might save you some reading Common Problems Ethernet cable Is the machine correctly connected to the ethernet cable Assuming Ethernet activity can be generated from another host eg attempt to ping the A60 repeatedly There is an LED the computer card second from left that shows Ethernet activity Some Transceivers eg Cabletron also have transmit receive and collision LEDs which are of great assistance at this stage Receive LEDs permanently on on both the Transceiver and the Computer Card Transceiver not connected to cable Collisions with every receive cable incorrectly terminated Receive at transceiver but not at Computer Problems with the Transceiver cable There have been some strange problems related to particular Tranceivers if you are experiencing problems such a a lot of retrys and you have more than one type available try a different one If possible use a transceiver with SQE turned of
57. rogram on a Unix system using the socket interface The first is a simple SunView application intended to demonstrate use of the Berkeley Socket interface and remote control of the A60 over Ethernet It consists of three files demo c the Ethernet interface to the A60 panel c a simple Suntools panel and a60 icon an icon used by the program To compile it you have issue the following command assuming you have access to the appropriate libraries cc demo c panel c Isuntool Isunwindow Ipixrect o demo There can only be one connection to A60 rlogin open at a time so if the window does not appear the A60 connection must already be open _ The program makes no attempt to interpret or dispose of any output from the A60 this is just being buffered up This should not prove to be a problem since there is no echo unless the rlogin was opened up with the string Osimon 0simon 0sun 9600 0 Rlogin turns off echo if the terminal speed parameter is omitted The second program demonstrates transfer of an RGB image directly into the A60 from a program simulating the operation of the rep command It does not use the SunView interface In the form presented it has very limited use since it always transfers the image to a hard coded frame number If the image is to be in YUV format the file extension specified in the command string and the transfer length will be different Note that this program will not copy to a normal Unix host beca
58. rror demo socket exit 3 bzero char amp skt sizeof skt bcopy a60 gt h_addr char amp skt sin a60 h length skt sin family a60 gt h_addrtype skt sin_port rlogin_service gt s_port if connect sd char amp skt sizeof skt 0 perror demo connect exit 3 write sd login str sizeof login_str n read sd tmp_str 20 printf read d n n write sd command_str szef command_str n read sd tmp str 20 printf read d n n write sd file str sizeof file_str 1 n read sd tmp str 20 printf read d n n 57 Appendix This information is provided for those who intend to write their own applications to manually access the file transfer and remote control services on the A60 TCP IP Packet Dump The following is a complete dump of a packet in case anyone out there is interested Physical Link Network Transport AA AA AA AA AA AA AA AB Ethernet Preamble and sync 00 00 76 60 FFFF Destination Addr 08 00 20 01 FF 90 Source Addr 08 00 Type 45 00 Version Header len Type of Serv 00 35 Length FE 7D 0000 ID Fragment Stuff OF 06 Time to live Protocol 90 2B Header Checksum 09 C801 Source Address CO 09 C8 05 Destination Address 2183 Source Port 00 17 Destination Port 18 4A OE DB Sequence 00 00 00 3B Acknowledge 50 18 Flags 10 00 Window AA CF Checksum 00 00 Urgent Pointer 68 65 6C 6C 6F 20 77 6F 72
59. s Internet address to access the services supported by the A60 TEP licati This section gives a brief outline of the functions of each of the used in the A60 and the way they interact Typical File Transfer Take for example an rcp transfer on a Unix system To invoke rcp the user types unix rcp file yuv 60 37 which causes a connection to be opened to the rcp server on the Abekas A60 The hostname is the name used to refer to the A60 on the users machine Somewhere there will be a file etc hosts on unix which gives the mapping between the name or some other optional alias and the Internet Address that has been assigned for the A60 A typical entry in etc hosts has the following form 192 5 200 9 a60 Rcp will first find the Internet address of the remote host by referring to the etc hosts file Then it has to find the lower level Ethernet address that corresponds to the machine with that Internet address The Ethernet address will either be the address of the A60 itself or a Gateway device on the local ethernet through which the A60 can be reached In some cases the host computer may have retained this information from a previous transaction but for the first transfer to an unknown remote host the local host has to resolve the Internet Ethernet address mapping To do this it uses the Address Resolution Protocol ARP ARP involves sending a broadcast packet to all the hosts on the network Only the
60. s that the Yellow Pages are not running ypbind is the name of the program that accesses the YP service ourhost ypwhich yphost Says the Yellow Pages are originating from the host called When the yellow pages are running network nodes only consult their own tables at boot time after this requests for system configuration such as hostnames are provided by the yellow pages service The new hostname need only be entered on the YP server machine It then has to be pushed out to all the other clients First login on the YP server machine either over the net or by actually walking over to the YP server ourhost rlogin yphost 1 root Update the etc hosts file as described above Now we have to update the dynamic version of the host table yphost cd etc yp yphost make hosts Updated hosts Pushed hosts A60 Ethernet Manual etc ethers There is a further refinement for certain networks that allows the A60 to ask the network what its Internet address is by way of the Reverse Address Resolution Protocol RARP This requires an addition to the file etc ethers Note that this step will not usually be necessary since the A60 stores its Internet address in Non Volatile RAM It only uses RARP if the RAM contents are lost or the Internet Address is manually set from the control panel to 0 0 0 0 and the machine is restarted twice To find out if a host supports RARP try the following yphost ps ax grep it
61. s the external reference selected correctly If the disks are making strange noises trying to lock to a non existant sync switch the Internal External Sync select to Internal the right RGB Transfers If the data comes out stepped diagonally as a result of an FTP check that TYPE IMAGE was specified before the send some FTP programs at the host end expand out CRLF sequences in the defauit ASCII mode If YUV data can be transferred OK but RGB comes out pink and green Is the file extension being specified correctly Finally the data comes out green there may be problems with the MAC chip Colorized Video If the computer card is changed and the existing material on the disk is suddenly weird colors you probably forgot to change the Fiaw Map proms 19E and 23E to the new computer card Field Service Call 40 In the event that you decide to call Abekas Field service for an Ethernet related problem it helps if you have the following information to hand Software version numbers see the diagnostic menu 4 System configuration Types of host computers Operating system Network Configuration how many hosts is it busy Application used eg Rlogin FTP homegrown rcp Which direction were you transferring data Was it an RGB or YUV transfer Did the connection hang up or the A60 crash can you still draw color bars A60 Ethernet Manual Doing your own Debugging if you are really keen there is copious debug information
62. should show you al the processes with anything to do with RARP apart from the line that says grep rarp which is part of the command you just typed there ought to be a mention of usr etc rarpd the RARP Daemon the process that catches RARP requests is running If this is the case you can add the Ethernet address of the A60 to the etc ethers yphost vi etc ethers A typical entry in ethers is 0 0 76 60 FF FF 60 Again if the Yellow Pages is running you have to force it to update its copy of the ethers file yphost cd etc yp yphost make ethers If the Internet address on the A60 is set to all zeros the A60 will attempt try to find its address from the network when it is rebooted twice If you watch the Internet Address Menu it should show the correct address when it finds it the Ethernet address of one of the Internet hosts changes you might have to flush the 014 entry from the ARP tables in the kernel This can be achieved by using the arp command ourhost etc arp d a60 This deletes the table entry and forces the host to use ARP the next time a connection is required therefore obtaining the latest Ethernet address 29 30 A60 Ethernet Manual Implementation No The following notes list the specific aspects of the implementation of TCP IP on the A60 Ethernet Address The unique Ethernet Address for each machine is set in Software PROM for the 68000 top 6 bytes of the 27256 at location 7C on the c
63. source in out records from various sources pattern input or specific rame number Defaults to a single frame Using the trailing plus sign it is possible to record odd numbers of fields record 10 10 will record a single field and record 11 13 will record three fields starting on an odd boundary protect 18 out write protects the given range the range is inclusive in frame mode the range is rounded up to the second field unprotect in out unprotects the given range pattern pattern num draws the given pattern into the store mode display model with no parameters returns the current mode Note that to change the mode frame or field has to be typed in full enable unlock the A60 Keyboard see Disable disable locks the A60 keyboard prevents accidental use of the trackerball can be overridden by pressing a number followed by the stop button on the keyboard freeze freezes the framestore unfreeze unfreezes the ramestore note that unfreezing will not change the display unless the disk is already playing input 601 input selects video input 1 or 2 defaults to input 1 recrel n fields record relative ie like the control panel from current position for n fields defaults to a frame 25 26 man help command or parameter the help command provides information on individual commands or parameters With no arguments it lists all the commands available help undo
64. t with debug on the machine vill run more slowly especially with the lower levels of debug where it has to print several lines per packet The A60 debug represents non printing ASCII vales as a backslash followed by two hex digits The buffering for the debug port is fairly crude so if there are large amounts of debug information being transmitted the buffer can wrap round and information can become garbled High Level Debug 42 If the Teinet Socket debug bit 400 is set the following messages will be generated 100 simon OO0debug Lines starting with five stars show what arrives on a packet by packet basis The text is enclosed in double quotes and any non printing characters appear as backslash and two hex digits RSH EXIT TELNET recv opt DO SUPPRESS GO AHEAD the Application debug bit 80 is set the following messages will be printed Lines starting with three stars show significant events such as opening and closing connections RSH EXEC GOT FNAME RSH EXEC play TELNET EXEC goseg A60 Ethernet Manual TCP Debug Port Numbers 20 FTP Data 21 FTP Command 23 Telnet 513 514 rsh and rep These are the well known port numbers used by the A60 TCP 1022 send 4 102 9 200 3 1021 tcb 4 Seq 33741057 Ack 1 Win 4096 SYN ACK Intitially TCP debug describes each packet by the local port number and the foreign Internet Address and port Once Established the TCP conn
65. the packet addresses This allows the packet traffic to be routed to several different processes or users within a particular machine TCP connection is characterized by the combination of local and remote Internet addresses and the local and remote port numbers So for instance several people may be logged in on a machine through the port assigned to the remote login service If two of the users originate from the same machine they will have to be on different ports on their local machine The TCP software can then identify uniquefy which connection a packet belongs to Some of the lower port numbers normally fess than 1024 are reserved for system functions these are we pown port numbers that are published for other computers wishing to use a particular service Opening connections to these ports is normally a privileged operating system function FTP 21 Telnet 23 rsh rlogin 513 Commonly used TCP port numbers The TCP packet header also carries Sequence and Acknowledge numbers The Sequence number represents the position of the first byte of this packet in the transmitted data stream The Acknowledge represents the byte after the last fully reassembled byte of the data stream received In other words the Receiving TCP can buffer several packets that may be out of sequence but the Acknowledge number will only increase once the incoming data is complete up to that byte number 10 A60 Ethernet Manual Sequence numbers are fixed
66. tion required to pass it from one host to another across different networks The intention is that a gateway that is passing the packet from one network to another need only examine the IP header to determine the routing information The Internet Protocol also provides a mechanism for breaking packets into smaller fragments for passing them over a network with restricted packet size Abekas Internet Addresses Internet address is a four byte number conventionally expressed as four decimal numbers 0 255 separated by dots eg 192 9 200 5 The Internet Address can be subdivided into two parts The first is referred to as the Network number and the second as the local address All the machines on the same local network should have the same Network Number but different Local Addresses If a host is asked to send a packet to a remote host with a different Network number it will assume that the remote host is on a different network and attempt to find a gateway to it Network Numbers for Internet sites are assigned by the ARPA authorities the local addresses are chosen by the focal system administrator There are many Ethernet networks that are not actually part of the Internet and only use a default Network number There are three classes of internet address based on the the Network number For a class A address the first byte of the internet address will be less than 128 the local address is then formed by the lower three bytes allowin
67. use it bypasses the normal access permissions required by Unix safe the knowledge that the A60 does not require a reserved originating socket number below 1024 The program normally has to be running as root to bind to a privileged socket 49 Abekas demo c 50 demo c quick lash up to show remote control of A60 from within a Suntools app using TCP IP Copyright 1987 Abekas Video Systems Inc Based on example proggys in the IPC Primer in Networking on the Sun Workstation include lt stdio h gt include lt netdb h gt include lt errno h gt include lt sys types h gt include lt sys socket h gt include lt netinet in h gt char login_str Osimon Osimon Osun 0 char play_fwd_stri playin char play_back_str play 1 n char stop_str stop n int sd global socket descriptor open_connection struct sockaddr in skt struct servent service struct hostent a60 int lport char c tmp_str 80 str 80 if rlogin service gelservbyname login tcp NULL fprintf stderr demo tcp unknown service n exit 1 if a60 gethostbyname a60 NULL fprintf stderr demo a60 unknown host n exit 1 A60 Ethernet Manual bzero char amp skt sizeof skt bcopy a60 gt h_addr char amp skt sin_addr a60 gt h_length skt sin_addr s_addr INADDR_ANY if sd socket AF_IN

Abekas A60 Digital Disk Recorder Ethernet Manual Aug88

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